At first glance you probably wouldn't think this is a comb jelly.  Although resembling a hydromedusa, the short, whitish comb rows reveal its true affiliation.  The body is shaped like the bell of a medusa and may be up to 15 cm diameter, but usually more like 2 to 3 cm in central California waters.  A central cone-shaped peduncle holds the mouth slit.  A pair of small tentacles hang from the sides of the peduncle.  With its transparent, colorless body, this comb jelly is usually very difficult to see.  In a manner similar to lobate comb jellies, Thalassocalyce holds the "bell" wide open to capture zooplankton prey.  The bell contracts when bringing captured prey to the mouth or following a disturbance.  Compared to other comb jellies, this species has limited swimming ability.  It is an occasional visitor to central California waters, particularly during periods in the fall when warmer oceanic waters invade nearshore areas.  Thalassocalyce is also known from surface and midwater habitats in the Atlantic Ocean and Mediterranean Sea.

All photographs © David Wrobel and may not be used or copied without permission!